The invention relates to vehicles having belt drive systems and, more particularly, to vehicles, such as riding mowers, which utilize a transaxle, also functioning as a gear box and as a brake, having a single reverse and forward gear ratio.
It is known to use a transaxle, which functions as a brake and a gear box, on vehicles such as riding mowers, having a single gear ratio between the transaxle input and output in the forward and reverse modes. In such application, it is known to have the vehicle's engine drive a first belt which acts either directly or indirectly on a variator which in turn causes a second belt to drive the input sheave to the transaxle. By varying the tension on the first belt, the variator increases or decreases the speed of rotation of the second belt. The benefit of using a vehicle belt drive, as described, is that the performance characteristic of a hydrostatic drive may be simulated without incurring the requisite expense associated with conventional hydrostatic transmissions. With a belt drive system, a vehicle operator may select, from a plurality of vehicle speeds, that one speed uniquely suited for the particular situation.
It is common practice to mount a plurality of control levers and pedals on riding mowers employing a transaxle of the type aforedescribed. It is conventional to use separate controls to shift the transaxle for directional change and to vary the speed of the belt drive.
However, if vehicle direction and speed could be controlled by a single control lever much like that employed in conjunction with vehicles having hydrostatic transmissions, it would enhance operator convenience and simplify the operation thereof. Additionally, if a means were provided whereby an operator could resume a previously selected speed subsequent to temporarily slowing the vehicle to perform ephemeral tasks such as maneuvering close to trees, buildings, etc. without having to shift speeds by moving a speed control lever, the operation thereof would be further simplified and operator convenience would be further enhanced.
Thus, there is a need for a single lever control for a vehicle belt drive which provides for both mode and speed control; which provides for speed control without shifting the control lever; which provides for the resumption of an originally set speed after slowing for any reason without shifting the control lever and which provides for simplified operation and operator convenience.